1. Field of the Invention
This invention relates to housings for electrical and related telecommunication equipment. More particularly, it relates to a novel and highly effective vault that affords easy servicing of such equipment and maximum protection of the equipment between visits by service personnel, and that can be accommodated within the space provided by existing easements for such equipment.
2. Description of the Prior Art
Cross-connect equipment is standard in the telephone industry and well known to those skilled in the art. It is described in numerous patents and other printed documents and available from a number of commercial sources. The present invention is not characterized by the details of such equipment.
Telephone companies have for years struggled with the fact that on about every street corner in the US and other countries there is a large gray box or cabinet that houses telephone cross connect equipment. The boxes present a number of problems. First, they are an eyesore to an already cluttered urban landscape. Second, they are a liability issue as they typically encroach on pedestrian sidewalks. Third, since they are located at street corners they are the unintended targets of vehicles that routinely run them over, knocking out telephone service for local customers and costing the telephone companies a lot of money to repair.
One proposed solution has been to devise a method for placing the cross-connect equipment in waterproof vaults below grade. The problem is that you cannot simply lower the contents of the cabinet into an underground vault. The cross-connect equipment is mounted on panels that a technician can access from both front and back. Providing adequate access to the panels would require a very large vault, since a technician must be able to walk completely around the panels. The cost of such a vault is prohibitive, not to mention the fact that there is not enough space on the street corners where the telephone companies have existing easements.
An underground vault needs to have approximately the same footprint as the above-ground cabinet it replaces. To accomplish this, companies have been pursuing a “pop-up” cabinet, in which the cross-connect equipment is mounted on a springloaded panel that is then tilted forward so that it is flush with the sidewalk and covered with a waterproof door. To service the cross-connect equipment, the technician opens the door, tilts the panel up, and steps down into the vault, which is about 36 inches deep. When finished, he steps back up on to the sidewalk, folds the panel forward, and closes the waterproof door.
The problem with this design is meeting telephone company requirements for failure testing of the telephone cables that get flexed when the panel pops up. The panels must be capable of popping up 24,000 times without the telephone cables breaking from the flexing. To date no one has come up with a solution for this cable stress. In addition there is some concern about panel frames accidentally releasing during servicing of the equipment and trapping or injuring a technician.